Plumbing systems will have a series of valves controlling the water flow throughout the property. This includes isolating sections of the pipe run for maintenance. The most important valve is the stop valve that controls the flow of water from the mains supply into the property. In the event of an emergency it is important that you know where to find the stop valve.
Isolating valves come in a range of designs and are used for shutting off the water supply to small areas of the plumbing system. For example if a tap needs replacing, then its water supply would firstly need to be turned off, so the valve located close to the tap would be used to achieve this. Isolating valves can be metal or plastic but it is important to remember that some plastic valves are only suitable for hot water up to a certain temperature, which will be indicated on the outside of the valve. In older plumbing systems isolating valves may have tap handles but more modern valves are opened and closed using a slot-head screwdriver. When the slot is in line with the pipe the valve is open and closed when it is at 90° to the pipe. As with the stop valve, isolating valves must be fitted correctly in relation to the flow of water and this is indicated by an arrow on the outside of the valve.
A radiator bleed valve is situated on one side at the top of the radiator. The valve is loosened with a special key.
This is the connection between the handwheel and lock-shield valves and the radiator.